This relates generally to imaging devices, and more particularly, to imaging devices having pixel arrays with selective gain pixel readout capabilities.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an array of image pixels arranged in pixel rows and pixel columns. Row control circuitry is coupled to each pixel row over row control lines for providing pixel control signals to each image pixel in the pixel row. Image pixels are often operated in a low gain mode for capturing images of brighter scenery and in a high gain mode for capturing images of darker scenery.
In conventional imaging systems, row control circuitry provides global control signals to each pixel the array to instruct every pixel the array to operate in either the high gain mode or the low gain mode. However, scenes to be imaged often include both brighter and darker portions across the array. Performing image capture operations using conventional image sensors that control image pixels in a pixel array to operate in the high gain or loss gain mode may thereby cause some image pixels in the array to generate excessively noisy or over-saturated image signals, which can generate unsightly image artifacts in the final captured image.
It would therefore be desirable to be able to provide imaging devices with improved means of capturing and processing image signals.